CVE-2025-66090 is a DOM-based Cross-site Scripting (XSS) vulnerability identified in the SKT Skill Bar plugin by sonalsinha21, affecting versions up to and including 2.5. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, specifically within client-side scripts, allowing malicious actors to inject arbitrary JavaScript code into the victim's browser environment. Unlike traditional reflected or stored XSS, DOM-based XSS occurs entirely on the client side, making it harder to detect and mitigate. Attackers can exploit this by crafting malicious URLs or payloads that, when accessed by users, execute unauthorized scripts. These scripts can steal session cookies, perform actions on behalf of the user, or redirect users to malicious sites. The vulnerability does not require authentication, increasing its risk profile, and no user interaction beyond visiting a malicious link is necessary. Although no public exploits have been reported yet, the widespread use of WordPress and its plugins, including SKT Skill Bar, means that many websites could be vulnerable. The lack of a CVSS score indicates that the vulnerability is newly published, and no official severity rating has been assigned. The vulnerability's impact primarily affects confidentiality and integrity of user data and can also affect availability if exploited to perform disruptive actions. The absence of patches at the time of publication necessitates immediate attention to monitoring for updates and implementing interim mitigations such as input sanitization and CSP enforcement.

For European organizations, especially those operating WordPress-based websites with the SKT Skill Bar plugin, this vulnerability poses a significant risk to user data confidentiality and integrity. Exploitation could lead to session hijacking, unauthorized actions performed in the context of authenticated users, and potential data leakage. This is particularly critical for e-commerce platforms, financial services, and any organization handling sensitive personal data under GDPR regulations. The vulnerability could undermine user trust and lead to regulatory penalties if personal data is compromised. Additionally, successful exploitation might facilitate further attacks such as phishing or malware distribution. The impact extends to brand reputation and operational continuity if attackers leverage the vulnerability to disrupt services or deface websites. Given the client-side nature of the vulnerability, users accessing affected sites from any location, including Europe, are at risk, amplifying the threat landscape for European enterprises with international user bases.

Organizations should prioritize monitoring for official patches or updates from the SKT Skill Bar plugin developer and apply them immediately upon release. Until patches are available, implement strict input validation and sanitization on all user-supplied data that could be processed by the plugin, particularly data reflected in the DOM. Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks. Conduct thorough code reviews and security testing of the plugin's integration within the website environment. Educate users and administrators about the risks of clicking on suspicious links and implement web application firewalls (WAFs) with rules targeting XSS attack patterns. Regularly audit and update all WordPress plugins to minimize exposure to known vulnerabilities. Consider disabling or replacing the SKT Skill Bar plugin if immediate patching is not feasible and the risk is deemed unacceptable. Finally, ensure incident response plans include procedures for XSS attack detection and remediation.